QUALITATIVE BACTERIOLOGICAL ANALYSIS. 129 



low power the colonies have a yellowish colour and a dark, 

 almost opaque, granular centre. 



Gelatine-stab. There is a white growth on the surface and 

 along the line of inoculation. The gelatine is not liquefied, 

 and acquires a steel-blue colour, which later becomes almost 

 black. 



Agar. A greyish-white growth appears, and the medium 

 becomes almost brown in colour. 



Glucose-gelatine. No gas formation. The gelatine acquires 

 a deep Prussian-blue colour. 



Milk. Not coagulated after several days incubation, and 

 becomes slightly alkaline, with a faint bluish tinge. In unsteril- 

 ised milk it produces a sky-blue colour. 



Broth. A diffused growth. Later, a pellicle forms on the 

 surface, and the broth acquires a blue colour. 



Potato. It forms a yellow restricted growth, and the potato 

 assumes a greyish-blue colour. 



Blood-serum. It grows, but does not produce any pig- 

 ment. 



Microscopical Characters. A thin motile bacillus, which forms 

 spores at the ends of the rods. According to Fliigge, the spores 

 seen by Hueppe are only involution forms. It grows at room 

 temperature and blood-heat. It does not stain with Gram. 

 NOTE. Jordan stated that the specimens which he isolated 

 from sewage did not grow as well at 37 C. as at 21 C., 

 and were not " very motile." He also failed to observe any 

 true spores. 



Bacillus Acidi Lactici. 



This bacillus was isolated by Hueppe from sour milk, and 

 was found in the Freiburg water by Tils. 



Gelatine Plates. The surface colonies appear as circular white 

 masses with an irregular outline and resemble those of B. coli ; 

 later, leaf-like expansions grow out from the margin. The 

 gelatine is not liquefied. 



Gelatine-stab. There is a white growth on the surface, which 

 later shows leaf-like expansions. Along the stab there is a 

 white growth consisting of small white centres. 



Agar-slope. A thick, w r hite, adhesive growth. 



